Nanoparticles, Laser Light Help Fight Breast Cancer

The insidious beauty of cancer is that it disguises itself as normal cells fooling the immune system until it can grow into proportions that are unmanageable or untreatable. Researchers have thought if they could help the immune system identify and fight cancer cells they could improve the patient’s prognosis.

Hope on that front could be on the way as a team of researchers at the University of Georgia, Athens, has developed a new technique that uses nanoparticles to reprogram immune cells so that they can recognize and attack cancer cells. The method has shown promise in early lab test and the researchers now are planning to expand their program.

The human body constantly fights off bacteria and viruses through the immune system, which keeps the invaders at bay. While good at its job, the immune system is not perfect.

Most cancerous cells, for example, avoid detection because they closely resemble normal cells, allowing the cancerous cells to multiply and grow into life threatening tumors while flying under the radar of the immune system. Shanta Dhar, a University of Georgia assistant professor of chemistry is using nanoparticles and laser light to give the immune system a leg up in its recognition of cancer cells.

“For the first time we can stimulate the immune system against breast cancer cells using mitochondria-targeted nanoparticles and light using a novel pathway,” Dhar says. “We are able to activate the immune system in a way it is not normally activated. This helps the body to naturally fight the cancer.”

In their experiments, Dhar and her colleagues exposed cancer cells in a petri dish to specially designed nanoparticles. The nanoparticles invade the cells and penetrate the mitochondria—the organelles responsible for producing the energy a cell needs to grow and replicate.

Then they activated the nanaoparticles inside the cancer cells by exposing them to tissue penetrating long wavelength laser light. Once activated, the nanoparticles disrupt the cancer cells normal processes.

“After laser irradiation, a cascading effect of signals occur leading to cell death,” she explains. “This specialized cell death then releases special proteins and signals that immune cells can pick up.”

When the dead cells were collected and exposed to dendrictic cells, one of the core components of the immune system, something remarkable happened, according to Sean Marrache, a graduate student in Dhar’s laboratory.

“By targeting nanoparticles to the mitochondria of cancer cells and exposing dendrictic cells to these activated cancer cells, we found that the dendrictic cells produced a high concentration of chemical signals they don’t normally produce, and these signals have traditionally been integral to producing effective immune stimulation,” he says.

“We basically use the cancer against itself,” Dhar adds. “The dendrictic cells recognized the cancer as something foreign and began to produce high levels of interferon-gamma, which alerts the rest of the immune system to a foreign presence and signals it to attack.”

She adds that the ability of the nanoparticles to target a specific location within the cell is a key.

“They are able to localize inside the location responsible for a majority of the energy production” of the cell, Dhar says.

She adds that if the process were to become a treatment, doctors could biopsy a tumor from a patient and kill the cancerous cells with nanoparticles. They could then produce activated dendrictic cells in bulk in the lab before the cells are injected back into the patient. Once in the bloodstream, the newly activated cells would alert the immune system to the cancer’s presence and destroy it.

While the work is still in early stages (majority of the studies have been done outside of the body) and used on specific cancer cell lines (human breast adenocarcinoma and mouse metastatic breast cancer lines), plans are to move into a mouse cancer model and test it on a wider range of cell lines.

Dhar says she thinks the “technique could help patients with advanced metastatic disease that has spread to other parts of the body. If we can refine the process further, we may be able to use similar techniques against other forms of cancer as well.”